21638 leans slightly Republican by roughly 12 points: about 44% of voters vote Democratic and 56% Republican.
About 87% of adults in 21638 typically vote, above the U.S. average of about 62%. Among adults in 21638, ~38% vote Democratic, ~49% Republican, and ~13% don't vote. The map below shows estimated turnout by block group.
How 21638 compares
Among zip codes within 15 miles, 21638 leans more Republican than 6 of 17 neighbors.
21638 runs about 42 points more Republican than Maryland as a whole. Maryland leans Democratic overall, while 21638 is one of the few Republican-leaning pockets.
Why 21638 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 21638, not a ranked or complete list of what matters most.
21638 votes against the grain of Maryland. Maryland leans Democratic overall, while 21638 runs about 42 points more Republican. A high family-household share predicts Republican voting, and about 77% of households in 21638 are family households, above 86% of zip codes.
Park access and Republican lean
Places with low park coverage tend to lean Republican; 21638, MD sits in the bottom quarter nationally on this measure. Park access does not change how people vote; it tends to track denser, higher-income areas.
Why turnout in 21638 looks the way it does
Turnout in 21638 sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
Sources and methodology
Precinct-level voting records used to fit the model come from Maryland State Board of Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.
Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.
Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.